filename has extra ;1

I use CDReader to extract files form ISO, sometimes it works correctly.
But when I try to extract files from "sc_office_2003_pro.iso", I founded every file has appended ";1", just like that I got "SETUP.EXE;1" who should be "SETUP.EXE".
Can anyone in the world tell me how can I get the right files form the ISO? Thanks
My C# code: